WooCommerce process HRK by Paypal

  add_filter('woocommerce_paypal_args', 'convert_hrk_to_eur');  

function convert_hrk_to_eur($paypal_args)
{  
    if ( $paypal_args['currency_code'] == 'HRK')
    {  
        $convert_rate = 7.5; //set the converting rate  or pull form the DB transients

        $paypal_args['currency_code'] = 'EUR'; //change HRK to EUR 
        
        $i = 1;  
  
        while (isset($paypal_args['amount_' . $i])) 
        {  
            $paypal_args['amount_' . $i] = round( $paypal_args['amount_' . $i] / $convert_rate, 2);  
            ++$i;  
        }  
  
    }  

    return $paypal_args;  

}